Coupling means for a riser string run from a floating vessel to a subsea well

ABSTRACT

A coupling means connects a riser string of tubing to a floating vessel over a subsea well to which the string is run by a support member, which in one version is a housing mounted beneath the rotary table on the vessel with a tubing hanger support means provided in the housing, and in another version is a support ring mounted in the sea beneath the vessel by constant tension cables run from the vessel. A string of tubing is run through the bore of the rotary table and a central bore through the support member to the subsea well. The tubing hanger supporting the riser string is also run through the table bore and is landed in the support member positioned beneath the table. The support member also in one version has a fluid line coupling means provided integrally thereof for automatically connecting the interior of the riser string of tubing to a vessel associated fluid line upon the landing of the tubing string in the support member. The support member, in the latter version, is also provided with a diverter insert, a blowout-preventer insert, and a packer insert to provide radial passages and a collector passage within the support member to conduct well fluids from a space between an operating string and the surrounding riser string while closing the upper end of the support member to prevent the escape of fluids therefrom.

[ Feb. 12, 1974 l [75] Inventor:

[ 1 COUPLING MEANS FOR A RISER STRING RUN FROM A FLOATING VESSEL TO A SUBSEA WELL Bruce J. Watkins, Palos Verdes Estates, Calif.

[73] Assignee: Regan Forge and Engineering Company, San Pedro, Calif.

[ Filed: Sept. 28, 1971 Appl. No.: 184,444

[52] US. Cl. 166/5, 285/18 [51] Int. Cl E21b 7/12 [58] Field of Search 175/5, 7, 8, 9, 10, 214;

Primary Examiner-Marvin A. Champion Assistant ExaminerRichard E. Favreau Petersen 175/7 X [5 7] ABSTRACT A coupling means connects a riser string of tubing to a floating vessel over a subsea well to which the string is run by a support member, which in one version is a housing mounted beneath the rotary table on the vessel with a tubing hanger support means provided in the housing, and in another version is a support ring mounted in the sea beneath the vessel by constant tension cables run from the vessel. A string of tubing is run through the bore of the rotary table and a central bore through the support member to the subsea well. The tubing hanger supporting the riser string is also run through the table bore and is landed in the support member positioned beneath the table. The support member also in one version has a fluid line coupling means provided integrally thereof for automatically connecting the interior of the riser string of tubing to a vessel associated fluid line upon the landing of the tubing string in the support member. The support member, in the latter version, is also provided with a diverter insert, a blowout-preventer insert, and' a packer insert to provide radial passages and a collector passage within the support member to conduct well fluids from a space between an operating string and the surrounding riser string while closing the upper end of the support member to prevent the escape of fluids therefrom.

25 Claims, 3 Drawing Figures P'Arsmmfim 1 j 3,791,442

sum 1M2 INVENTO/Q B2005 J: mT//N (QT To/eA/Es s COUPLING MEANS FOR A RISER STRING RUN FROM A FLOATING VESSEL TO A SUBSEA WELL BACKGROUND OF THE INVENTION The present invention relates in general to subsea well apparatus for coupling a string of tubing, as a riser string, to a floating vessel over a subsea well to which the string is run. More particularly, the present invention relates to a coupling means positioned beneath the bore of a rotary table structure provided upon the floating vessel to allow the running of the string of tubing through the rotary table bore and the landing of a riser string hanger means in the support member.

Conventionally, in subsea well drilling and production operations, a vessel or platform floating on the surface of the sea is connected to a subsea wellhead by a riser string and an operating string, i.e., drilling or production string, is run from the vessel or platform through the riser to the wellhead therebelow. As the vessel is floating, it is constantly moving relative to the wellhead, and, therefore, the riser string is provided with a telescoping joint to compensate for this movement. I-Ieretofore, if the telescoping joint was located at the lower end of the riser string adjacent the wellhead, then the riser string was hung statically from the vessel directly. If the telescoping joint was located at the upper end of the riser string adjacent the vessel, then the riser string was dynamically hung from cables attached thereto, below the telescoping joint, and run from constant reel winches on the vessel to provide a constant lifting force. The lifting force is required to prevent the riser string below the joint from buckling under its own weight. The running and positioning of such strings has been very difficult and time consuming heretofore. I Also, conventional oil well operations, such as drilling, for example, requires that a hydraulic fluid, commonly called mud, be supplied to the drill bit to keep the bit clean and remove aggregate produced during drilling. A pressurized supply of such mud is kept on the vessel, and, typically, is fed by a supply line down the center of the drill string to the drill bit on the lower end thereof. The mud passes through the drill bit to clean it and is forced along with the displaced aggregate, etc., up the space between the drill string and the riser string back to the vessel where a return line receives the mud to return the mud to the supply tank on the vessel. With the heretofore used coupling means for coupling the return line to the strings, the riser string was not automatically coupled to the mud return line upon being hung from thevessel. Further, it was necessary to uncouple the return line each time a section of riser string was added or removed. Such manual connecting, disconnecting and removing of the mud return line each time the riser was located or a section of riser string was added required considerable time and effort, delaying production operations.

BRIEF DESCRIPTION OF THE INVENTION object wherein the method and apparatus allow for the running of the riser string of tubing through the rotary table bore through a path to a subsea well and the landing of a riser string hanger in a support member positioned beneath the rotary table.

It is also an object of this invention to provide an improved novel mud or fluid return line coupling between a vessel associated return line and a riser string run from and supported from such vessel to a subsea well apparatus, and particularly such a coupling which automatically connects the riser string to the vessel return line upon the landing or locating of theupper end of the riser string in association with the vessel.

Other and additional objects of this invention are to provide such a coupling means which is mounted to the underside of the otherwise conventional rotary table structure on the vessel or platform; to provide such a coupling means in which the upper end of the riser string may be landed to automatically connect to the return line on the vessel and to receive the operating or drill string therethrough; to provide such a coupling means which mounts a return line so as to permit sections of the string to be added to or removed therefrom without uncoupling the return line; and to provide such a coupling means which eliminates unproductive coupling and uncoupling of the return line to increase the productive operating time of the drilling or production operations on a well.

Generally stated, the coupling means of the present invention for coupling a riser string of tubing to a floating vessel over a subsea well to which the string is run includes the provision of a support member having a bore therethrough for the passage of tubing and means for supporting a tubing hanger to be landed in the support member. Means are provided for mounting the support member beneath the table with the support member bore aligned to the table bore so that, in accordance with the method and apparatus of the present invention, the riser string of tubing may be'run through the table bore to the well and the tubing hanger may be run also through the table bore and into landed engagement on the support member. In one exemplary embodiment of the invention, a support member is mounted on the vessel, preferably to the support structure for the rotary table to position it directly beneath and adjacent to the underside of the rotary table. In a second embodiment of the invention, the support member is mounted beneath the vessel in the sea by suitable means, such as constant tension cable run from constant tension reel winches provided upon the vessel.

More specifically, in a preferred exemplary embodiment of the method and apparatus for coupling a riser string to a floating vessel according to the present invention, the riser string support member is provided with a coupling means connected to a fluid line on the vessel. The support member is provided so that upon landing of the riser string by its hanger in the support member, the interior of the riser string is placed in fluid communication with the fluid return line on the vessel via the support member connection. Closure means, in accordance with the present invention, are also provided in the support member for directing, collecting, and guiding fluid returns from the well through the support member to the vessel associated return line and to provide a removable fluid sea] at the upper end of the riser string. Such seal preferably includes a diverter insert, a blowout-preventer insert, and a packer insert.

Further objects and advantages of the coupling means apparatus and method of providing a coupling between a riser string and a floating vessel over a subsea well, of the present invention, as well as a better understanding thereof, will be afforded to those skilled in the art from a consideration of the following detailed explanation of preferred exemplary embodiments thereof. Reference will be made to the appended sheets of drawings which will now be first described briefly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a subsea well assembly including a floating vessel located over a subsea well with guide lines and a riser string of tubing running from the vessel to the subsea wellhead with a preferred exemplary embodiment of coupling means, according to this invention, connecting the riser string to the vessel;

FIG. 2 is an enlarged, fragmentary, partially cutaway, side elevational view of the coupling means of FIG. 1 during the positioning therein of a riser hanger having a ball joint by a running tool to mount the upper part of a riser string thereto; and

FIG. 3 is an enlarged, fragmentary, partially cutaway, side elevational view of the coupling means with a ball socket joint riser hanger means landed therein, a di verter insert, a blowout-preventer insert, and a packing insert therein, said riser including a telescoping joint in its upper portion adjacent the vessel with cables from constant tension reel winches on the vessel supporting the lower part of the riser String.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, the preferred embodiments of coupling means apparatus and methods of coupling a riser string to a floating vessel will now be described in detail.

The subsea well assembly includes a vessel 12 floating on the surface of the sea 13 over a subsea wellhead 14 located on the sea bottom 15. The vessel 12 is tied to the wellhead 14 by wire guides 16 which will guide parts from the vessel 12 to the wellhead 14 for attachment thereto. The vessel 12 typically has a derrick l7 thereon over a well or opening through the vessel which facilitates the lowering of parts to the wellhead l4 and the raising of parts from the wellhead 14.

Referring now to FIGS. 2 and 3, the vessel 12 also includes a rotating table structure 20 located below the derrick 17. The structure 20 has I-beams 21 from the vessel 12 on which are mounted a stationary platform 22 which has a large hole therein for receiving and drivingly rotatably mounting a rotating table 23. The rotating table 23 has a square cross-section hole 24 therein for rotatively driving oil well tools. Sections of the rotary table 23 are removable to provide access to the area below the table 23 or to allow large oil well tools to pass therethrough. The derrick 17 is adapted to lower or raise oil well tools through the rotating table 23 in conventional manner.

The vessel 12 also typically has a pressurized supply of fluid, commonly called mud, which is for use with a rotating tool, as a drill bit, in the wellhead 14. The supply has a supply line (not shown) which connects to the operating string 45 to supply the mud down the center thereof to the wellhead 14 and to the lower end of the operating string for washing the rotating tool thereon.

After washing the tool, the mud is forced up a mud return space, indicated at 50 in FIG. 3, between the operating string 45 and the riser string 30 to be fed into a mud return line 51. Heretofore, the mud return line 51 was coupled directly to the upper end of the riser string 30 and has to be coupled and uncoupled each time the riser, or its sections were landed or removed. The coupling means, according to this invention, eliminates the steps of coupling, uncoupling, and recoupling the mud return line to the riser string.

Generally, the preferred exemplary embodiment of coupling means, according to this invention, is indicated at and is mounted to the table structure as seen in FIGS. 2 and 3. The coupling means mounts the upper part 32 of the riser string for releasably connecting the well fluid or mud return line 51 to the fluid return passage to conduit fluids therebetween. The coupling means 10 of the preferred embodiment includes an elongated housing 60, means for mounting the housing 60 to the table structure 20, connecting means for connecting the vessel associated mud return line 51 to the housing 60, hanger means for removably hanging the upper, part 32 of the riser string 30 from within the housing 60, and conducting means for conducting the mud from the mud return passage 50 to the connecting means 70. The conducting means 80 may include mud guide means 81 for guiding the flow of mud from the mud return passage 50 towards the connecting means 70 and housing closing means for closing the housing 60 about the operating string 45 above the mud guide means 81 to close the upper end of the mud return space 50 and thereby prevent mud from escaping therethrough.

The riser string 30 is constructed of many hollow tubing sections and is run from the vessel 12 to the subsea wellhead 14 to provide a conduit therebetween from which the sea 13 is excluded. Because the vessel 12 is floating on the surface of the sea 13, the riser string 30 is provided with a telescoping joint 31 which divides the string 30 into an upper portion 32 and a lower portion 35. The upper portion 32 has a ball and socket joint 33 from which an inner sleeve 34 depends to be received in the lower portion 35.

Where the lower portion 35 of the tubing string is so long that it will not support its own weight, as in the exemplary embodiment, a supporting ring or member 40 is provided as part of the coupling means for hanging the lower portion 35 of the tubing string from the vessel 12. The supporting ring 40 receives the tubing hanger 38 of the tubing string 35 which is run through the table bore, according to the method of the present invention, to land on the member 40. Ears 41 are provided on member 40 to which cables 42 are attached. The cables 42 are wound upon constant reel winches 43, of conventional construction, on the vessel 12 to carry the weight of the lower portion 35 of the riser string 30.

The housing 60 of the preferred embodiment of the mud return line coupling means 10 is best seen in FIGS. 2 and 3. The housing 60 is generally tubular in shape and has an open upper end 61 and an open lower end 62 with a hollow central bore 63 therebetween. The housing 60 is large enough that the central bore 63 therethrough will have sufficient dimensions for the riser string 30 to be passed therethrough by the derrick 17.

The means 65 for mounting the housing 60 to the table structure 20 includes, in the preferred embodiment, an annular flange 66 extending radially outwardly from the housing 60 at a location spaced slightly from the upper end 61. Vertically oriented triangular reinforcing flanges 67 are provided between the annular flange 66 and the housing 60. The flange 66 is for being secured to the lower flange of the l-beams 21 by a suitable means, such as welding, to coaxially locate the housing 60 below the rotary table. 23 for receiving the strings 30 and 45 therethrough.

Connecting means 70 is provided for connecting the vessel associated mud return line 51 to the housing 60. In the preferred embodiment, the connecting means 70 includes the provision of a tubular protrusion or outlet 71 on the housing 60 below the annular flange 66. The protrusion 71 extends radially outwardly from the housing 60 to terminate in an outer end 72. The outer end 72 is suitably sized to receive thereover the end of the mud return line 51, which is clamped thereto by a clamp 73. The protrusion 71 is provided with a central passage 74 which opens the hollow central bore 63 of the housing 60 to the mud return line 51 to conduct mud therebetween. The hanger means 75 for removably hanging the upper part 32 of the riser string 30 from within the housing 60 includes, in the preferred embodiment, a circumferential ridge 76 adjacent the upper end of the ball and socket joint 33, which provides a downwardly facing landing shoulder 77. The housing 60 includes an inwardly extending lower lip 78 at the lower end 62 thereof which provides an upwardly facing shoulder 79 which is suitably sized to landingly receive the shoulder 77 thereagainst to hang the riser string 30 from within the housing 60. It should be noted that the upper end of the ball and socket joint 33 which is the upper end of the riser string 30 is located below the entrance of the central passage 74 into the central bore 63 of the housing 60 so that conducting means 80 can be received within the housing 60.

Conducting means 80 is provided for conducting the mud from the mud return passage 50 to the central passage 74 of the connecting means 70. The conducting means 80, of the preferred embodiment, includes mud guide means 81 for guiding the flow of mud from the mud return passage 50 to the central passage 74 and housing closing means 90 for closing the upper open end of the mud return passage 50 above the mud guide means 81 to prevent the mud from escaping therethrough;

As best seen in FIG. 3, the mud guide means 81 includes the lower portion of a diverter insert 82 which is sized to be snuggly received in the bore 63 of the housing 60 above the ball and socket joint 33. The diverter insert 82 is provided with a vertical central bore 83 from which four radial passages 84 extend to open into a circumferential groove 85. When the diverter insert 82 is located in the housing 60, the circumferential groove 85 forms with the housing 60 and the ball and socket joint 33, a mud collecting cavity 86 which is aligned with and in communication with the central passage 74 of the connecting means 70 to direct the mud thereinto. v

The diverter insert 82 also acts as part of the housing closing means 80 for closing the housing 60 above the mud collecting cavity 86. An upper portion of the diverter insert 82 is suitably sized to besnuggly received in the upper end 61 of the housing 60 where it is retained by a latch dog 91 mounted to the housing 60 and typically hydraulically actuated. The diverter insert 82 has an upper annular cutout 92 into which is received a blowout-preventer insert 93 which is secured therein by a ring 94. The ring 94 has a spring latch mechanism 95 for latching a packer insert 96 inserted into the blowout-preventer insert 93 and ring 94. The packer insert 96 extends to sealingly engage the operating string 45 and completes the closing of the upper end 61 of the housing to prevent the escape of mud therefrom.

With the housing 60 mounted to the rotary table structure as disclosed herein, the end of the mud return line 51 is inserted onto the outer end 72 of the protrusion 71 and clamped by clamp 73 to remain so clamped until the line 51 needs to be repaired. The housing 60 is automatically ready to receive the riser string 30 therein. If another support member, as support ring 40, is needed, it is located directly beneath the housing 60 and coaxial therewith, while the derrick l7 lowers sections of the lower part 35 of the riser string 30 through the rotating table 23, through the housing 60, through the support ring 40, if required, down into the sea 13 to be guided by guide lines 16 to the wellhead 14. When the enlarged upper end passes through the housing 60, it will then land on the support ring 40 to hang the lower part 35 of the riser string 30 from the vessel 12 for receiving the upper part 32. As is illustrated in FIG. 2, the upper part 32 of the riser string 30 may be run by the hanger tool 46 through the rotating table 23, through the housing 60 until the inner sleeve 34 telescopes into the outer sleeve 37 to provide the telescoping connection at 31 and until the shoulder 77 of the ball and socket joint 33 lands on the shoulder 79 of the housing 60, thus landing riser string 30 within the housing 60. The hanger tool 46 is then removed.

An assembly of the packer insert 96, the blowout preventer 93, the ring 94, and the diverter insert 82 is preassembled and inserted into the upper end 61 of the housing 60 to rest on the upper end of the ball and socket joint 33. This assembly is held in the housing 68 by the latch dog 91 for receiving the operating string 45 therethrough. The operating string 45 extends down the riser string 30 and into the wellhead 14. The upper end of the operating string 45 is non-rotatably secured in the square cross section hole 24 to be rotatably driven by the rotating table 23 and the supply mud line (not shown) is connected thereto to supply the mud down the center thereof to the rotating tool (not shown) mounted on the lower end of the operating string 45. The mud from the tool is forced up the mud return space 50 to pass into the central bore 83 of the 'diverter insert 82, where its upward progress is blocked I to a subsea well, it should be apparent to those skilled in the art that the objects and advantages aforestated for the present invention have been attained. Once the floating vessel is located over the well with the rotary table bore positioned with a clear path between it and the well, the apparatus and method of the present invention allow the running of the riser string of tubing down through the rotary table bore and into landed engagement with a support member positioned beneath the table. Such support member, according to the method of the present invention, may comprise the ring means 40 positioned in the sea beneath the vessel, a housing mounted on the vessel beneath the table or, as in the preferred exemplary embodiment, a combination of the two to provide a telescoping joint connection between the upper end of the riser string and the floating vessel ready to receive additional tools, as a drilling string. Further, the riser string, according to the method and apparatus of the present invention, is automatically interconnected with a return line on the vessel upon the landing of the upper end of the riser string in the connecting means support member. Well fluid returns from within the riser are directed, collected, and passed to the vessel associated return line while the upperend of the riser string is sealed about an operating string run therethrough.

I claim:

1. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a rotary table mounted upon a support structure on said vessel and having a table bore therethrough positioned over a path to said well, said coupling means comprising:

a support member having a bore for the passage of tubing therethrough and means for supporting a tubing hanger landed in said member, and

means for mounting said member beneath said table with said member bore aligned to said table bore to allow the running of a string of tubing through said table and member to said subsea well and said tubing hanger through said table into landed engagement on said member, wherein said means for mounting said member is provided upon said vessel for mounting said member on said vessel beneath said table and to the support structure for said rotary table.

2. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a rotary table mounted upon a support structure on said vessel and having a table bore therethrough positioned over a path to said well, said coupling means comprising:

a support member having a bore for the passage of tubing therethrough and means for supporting a tubing hanger landed in said member, and

means for mounting said member beneath said table with said member bore aligned to said table bore to allow the running of a string of tubing through said table and member to said subsea well and said tubing hanger through said table into landed engagement on said member, wherein said means. for mounting said member is provided upon said vessel for mounting said member on said vessel beneath said table, and

wherein said member is provided with an outlet means for connection to a vessel associated fluid line provided on said vessel so that, upon landing of said riser string of tubing run through said table, said vessel associated fluid line is automatically placed in fluid communication with the interior of said tubing string supported by said member.

3. The coupling means of claim 2 wherein:

said vessel associated line is a mud return line for receiving mud return from said well through said riser string during drilling operations, a drill string is run through said member down within said riser string, providing a mud return passage therebetween, and

closure means are provided above said tubing hanger means and about said drill string for closing said member bore and said mud return passage during drilling operations.

4. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a rotary table mounted upon a support structure on said vessel and having a table bore therethrough positioned over a path to said well, said coupling means comprising a support member having a bore for the passage of tubing therethrough and means for supporting a tubing hanger landed in said member, and

means for mounting said member beneath said table with said member bore aligned to said table bore to allow the running of a string of tubing through said table and member to said subsea well and said tubing hanger through said table into landed engagement on said member, wherein said means for mounting said member is provided beneath said vessel and includes constant tension reel winches on said vessel and cables run between said member and said winches to position said member in said sea beneath said vessel.

5. The coupling means of claim 4 wherein a second support member having a bore for the passage of tubing therethrough is provided having a second means for supporting a second tubing hanger thereon;

a second means for mounting said second member is provided upon said vessel beneath said table with said second member bore aligned to said table bore; and

telescoping joint means are landed through said table bore upon said second support member for providing a telescopic connection between said riser string hung beneath said vessel and said second support member on said vessel.

6. The coupling means of claim 5 wherein said second member is provided with an outlet means for connection to a vessel associated fluid line provided on said vessel so that, upon landing of said riser string through said table on said first mentioned support member and the landing of said telescopic joint means into engagement with said riser and on said second member, said vessel associated fluid line is automatically placed in fluid communication with said riser string.

7. A fluid line coupling means for coupling a riser, run from a floating vessel to a subsea well, with a vessel associated fluid line automatically upon locating said landed within said housing upon running of said tubing through said housing bore to place the interior of said riser string in communication with the interior of said housing and its outlet to said vessel associated line.

8. The fluid line coupling means of claim 7 wherein:

said hanger means includes a telescoping joint connection with an upper part of said riser string.

9. A fluid line coupling means for coupling a riser, run from afloating vessel to a subsea well, with a vessel associated fluid line automatically upon locating said riser relative to said vessel, said coupling means comprising:

a housing and means for mounting it on said vessel, said housing having an outlet for connection of said vessel associated line to the interior of said houshanger means associated with the upper end of a riser string run from said vessel; and

means in said housing for supporting said hanger means, landed withinsaid housing with the interior of said riser string in communication with the interior of said housing and its outlet to said vessel associated line, wherein:

said vessel is provided with a rotary table mounted on a support structure and said housing is mounted to said support structure beneath said table, and

said housing has a through bore aligned with an opening through said table to allow running of said riser stringand its hanger means through said table to be landed in said housing.

10. The fluid line coupling means of claim 9 wherein:

said vessel associated .line is a mud return line for receiving mud returns from said wellhead through said riser string during drilling operations, a drill string is run through said housing from within said riser string, providing a mud return passage therebetween, and

housing closure means are provided above said riser hanger means and about said drill string for closing said through bore and said mud return passage during drilling operations.

11. A fluid line coupling means for coupling a riser, run from a floating vessel to a subsea well, with a vessel associatedfluid line automatically upon locating said riser relative to said vessel, said coupling means comprising:

a housing and means for mounting it on said vessel, said housing having an outlet for connection of said vessel associated line to the interior of said housing;

hanger means associated with the upper end of a riser string run from said vessel, wherein said hanger means includes a ball and socket joint connection with an upper :part of said riser string; and

means in said housing for supporting said hanger means, landed within said housing with the interior of said riser string in communication with the interior of said housing and its outlet to said vessel associated line.

12. In a subsea well assembly including a vessel floating on the surface of the sea overa wellhead on the sea bottom; a rotating table structure mounted in the vessel; a fluid line on said vessel for receiving well fluid; a riser string extendingfrom the vessel beneath the table structure and down through the sea .to the wellhead, said riser having a telescoping joint with relatively movable upper and lower parts which compensate for the motion of the vessel; and a removable operating string extending through the table structure, to be rotatively driven thereby and extending down through 'the riser string into the wellhead, said strings together providing a fluid passage therebetween, the improvement comprising the provision of:

coupling means mounted to the table structure and mounting the upper part of the riser string for releasably connecting the fluid line to the fluid passage to conduct fluid therebetween, said coupling means having a hollow interior of sufficient inside dimensions to permit insertion and removal of the strings without disconnecting the fluid line from the coupling means. 13. The invention as in claim 12 wherein the coupling means includes:

a hollow tubular housing with an open upper end and an open lower end, said housing including an annular flange adjacent the upper end thereof for being mounted to the table structure to locate the upper end' of the housing directly below and coaxial with the table structure, a tubular protrusion extending radially outwardly from the housing for connection to the fluid line to receive fluid from the housing, and an inwardly extending upwardly facing landing shoulderformed in the lower end of the housing for receiving a hanger means on the upper part of the riser string.

M. The invention as in claim 12 wherein the coupling means additionally includes:

a tubular insert sized for insertion into the upper open end of the housing to close the upper open end around the operating string run through the housing, said insert having radial passages and a circumferential groove therearound in communication with the radial passages to collect the fluid from the space between the operating string and the riser string and to deliver said fluid to said fluid line.

15. The invention as in claim 12 wherein the coupling means includes:

a hollow elongated housing with open upper and I lower ends;

means for mounting the housing to the table structure;

means for connecting the vessel associated fluid line to the housing;

hanger means for removably hanging the upper part of the riser string from within the housing; and

means for conducting fluid from the fluid passage to said connecting means.

1.6. The invention as in claim 15 wherein the means for conducting the fluid from the passage includes:

guide means provided in the housing and having a central bore in communication with the interior of the riser string landed in the housing, said guide means forming a circumferential fluid collecting cavity within said housing and having a plurality of radial passages connecting its central bore therewith, and

housing closing means provided in the housing about the operating string and over the guide means for closing the upper open end of the housing above the guide means to prevent the fluid from escaping therethrough.

17. The invention as in claim 16 wherein the housing closing means includes a tubular insert sized for insertion into the housing, said upper portion of the tubular insert being sized to mate with the hollow of the housing and shaped for receiving a packer insert therein, and includes a packer insert located in said upper portion for engaging the operating string run through the housing.

18. A method of completing the landing of a riser string between a floating vessel, having a rotary drilling table with a table bore therethrough, and a subsea well comprising the steps of:

running a string of tubing through said rotary table bore to said well, and

landing a hanger associated with said tubing on a support member associated with said vessel by running said hanger through said table bore into landed engagement with said member, wherein said member is supported from and beneath said vessel in the sea above said well and said step of running said hanger through said table bore includes the substep of running said hanger into the sea beneath said vessel and into said landed engagement in the sea above and spaced from said subsea well.

19. A method of completing the landing of a riser string between a floating vessel, having a rotary drilling table with a table bore therethrough, and a subsea well comprising the steps of:

running a string of tubing through said rotary table bore to said well, and

landing a hanger associated with said tubing on a support member associated with said vessel by running said hanger through said table bore into landed engagement with said member, wherein said member is supported beneath said table and said step of landing said hanger includes the substep of landing said hanger directly below and adjacent to the underside of said rotary table.

20. A method of completing the landing of a riser string between a floating vessel, having a rotary drilling table with a table bore therethrough, and a subsea well comprising the steps of:

running a string of tubing through said rotary table bore to said well,

landing a hanger associated with said tubing on a support member associated with said vessel by running said hanger through said table bore into landed engagement with said member, and

automatically connecting the interior of said string to a vessel associated line by the landing of said string and associated hanger upon said support member.

21. A method of completing the assembly of a subsea well assembly comprising the steps of:

mounting a tubular open ended housing to the rotating table structure of a floating vessel;

running a riser string through the table and housing; and

landing an upper end of said string in said housing.

22. The method of claim 21 including the steps of:

coupling a fluid line to the housing; and

automatically connecting the interior of the riser string to the housing and the line upon landing the riser string by its hanger means in the housing.

23. The method as in claim 22 additionally comprising the steps of:

inserting a preassembled insert assembly into the housing over the upper part of the riser string; and

running an operating string through the insert assembly, through the housing, and into the riser string while the insert assembly closes the upper end of the space between the operating and riser strings.

24. The method as in claim 23 additionally comprising the steps of:

removing the operating string through the housing without disconnecting the fluid lines; and

reinserting the operating string through the housing without disconnecting the fluid lines.

25. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a roatry table mounted upon a support on said vessel and having a table bore therethrough and positioned over a path to said well, said coupling means comprising:

a riser string supporting means having a central bore to allow passage of said string of tubing therethrough and means for supporting a riser string associated tubing hanger therein, and

means for mounting and positioning said supporting means beneath said rotary table with said central bore aligned to said table bore to allow running of said riser string of tubing through said table bore and central bore in said path to said well and said tubing hanger through said table to land on said supporting means. 

1. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a rotary table mounted upon a support structure on said vessel and having a table bore therethrough positioned over a path to said well, said coupling means comprising: a support member having a bore for the passage of tubing therethrough and means for supporting a tubing hanger landed in said member, and means for mounting said member beneath said table with said member bore aligned to said table bore to allow the running of a string of tubing through said table and member to said subsea well and said tubing hanger through said table into landed engagement on said member, wherein said means for mounting said member is provided upon said vessel for mounting said member on said vessel beneath said table and to the support structure for said rotary table.
 2. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a rotary table mounted upon a support structure on said vessel and having a table bore therethrough positioned over a path to said well, said coupling means comprising: a support member having a bore for the passage of tubing therethrough and means for supporting a tubing hanger landed in said member, and means for mounting said member beneath said table with said member bore aligned to said table bore to allow the running of a string of tubing through said table and member to said subsea well and said tubing hanger through said table into landed engagement on said member, wherein said means for mounting said member is provided upon said vessel for mounting said member on said vessel beneath said table, and wherein said member is provided with an outlet means for connection to a vessel associated fluid line provided on said vessel so that, upon landing of said riser string of tubing run through said table, said vessel associated fluid line is automatically placed in fluid communication with the interior of said tubing string supported by said member.
 3. The coupling means of claim 2 wherein: said vessel associated line is a mud return line for receiving mud return from said well through said riser string during drilling operations, a drill string is run through said member down within said riser string, providing a mud return passage therebetween, and closure means are provided above said tubing hanger means and about said drill string for closing said member bore and said mud return passage during drilling operations.
 4. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a rotary table mounted upon a support structure on said vessel and having a table bore therethrough positioned over a path to said well, said coupling means comprising: a support member having a bore for the passage of tubing therethrough and means for supporting a tubing hanger landed in said member, and means for mounting said member beneath said table with said member bore aligned to said table bore to allow the running of a string of tubing through said table and member to said subsea well and said tubing hanger through said table into landed engagement on said member, wherein said means for mounting said member is provided beneath said vessel and includes constant tension reel winches on said vessel and cables run between said member and said winches to position said member in said sea beneath said vessel.
 5. The coupling means of claim 4 wherein a second support member having a bore for the passage of tubing therethrough is provided having a second means for supporting a second tubing hanger thereon; a second means for mounting said second member is provided upon said vessel beneath said table with said second member bore aligned to said table bore; and telescoping joint means are landed through said table bore upon said second support member for providing a telescopic connection between said riser string hung beneath said vessel and said second support member on said vessel.
 6. The coupling means of claim 5 wherein said second member is provided with an outlet means for connection to a vessel associated fluid line provided on said vessel so that, upon landing of said riser string through said table on said first mentioned support member and the landing of said telescopic joint means into engagement with said riser and on said second member, said vessel associated fluid line is automatically placed in fluid communication with said riser string.
 7. A fluid line coupling means for coupling a riser, run from a floating vessel to a subsea well, with a vessel associated fluid line automatically upon locating said riser relative to said vessel, said coupling means comprising: a housing including a central bore for the passage of tubing therethrough and means for mounting it on said vessel, said housing having an outlet for connection of said vessel associated line to the interior of said housing; hanger means associated with the upper end of a riser string run from said vessel; and means in said housing associated with said bore for supporting said hanger means when the latter is landed within said housing upon running of said tubing through said housing bore to place the interior of said riser string in communication with the interior of said housing and its outlet to said vessel associated line.
 8. The fluid line coupling means of claim 7 wherein: said hanger means includes a telescoping joint connection with an upper part of said riser string.
 9. A fluid line coupling means for coupling a riser, run from a floating vessel to a subsea well, with a vessel associated fluid line automatically upon locating said riser relative to said vessel, said coupling means comprising: a housing and means for mounting it on said vessel, said housing having an outlet for connection of said vessel associated line to the interior of said housing; hanger means associated with the upper end of a riser string run from said vessel; and means in said housing for supporting said hanger means, landed within said housing with the interior of said riser string in communication with the interior of said housing and its outlet to said vessel associated line, wherein: said vessel is provided with a rotary table mounted on a support structure and said housing is mounted to said support structure beneath said table, and said housing has a through bore aligned with an opening through said table to allow running of said riser string and its hanger means through said table to be landed in said housing.
 10. The fluid line coupling means of claim 9 wherein: said vessel associated line is a mud return line for receiving mud returns from said wellhead through said riser string during drilling operations, a drill string is run through said housing from within said riser string, providing a mud return passage therebetween, and housing closure means are provided above said riser hanger means and about said drill string for closing said through bore and said mud return passage during drilling operations.
 11. A fluid line coupling means for coupling a riser, run from a floating vessel to a subsea well, with a vessel associated fluid line automatically upon locating said riser relative to said vessel, said coupling means comprising: a housing and means for mounting it on said vessel, said housing having an outlet for connection of said vessel associated line to the interior of said housing; hanger means associated with the upper end of a riser string run from said vessel, wherein said hanger means includes a ball and socket joint connection with an upper part of said riser string; and means in said housing for supporting said hanger means, landed within said housing with the interior of said riser string in communication with the interior of said housing and its outlet to said vessel associated line.
 12. In a subsea well assembly including a vessel floating on the surFace of the sea over a wellhead on the sea bottom; a rotating table structure mounted in the vessel; a fluid line on said vessel for receiving well fluid; a riser string extending from the vessel beneath the table structure and down through the sea to the wellhead, said riser having a telescoping joint with relatively movable upper and lower parts which compensate for the motion of the vessel; and a removable operating string extending through the table structure, to be rotatively driven thereby and extending down through the riser string into the wellhead, said strings together providing a fluid passage therebetween, the improvement comprising the provision of: coupling means mounted to the table structure and mounting the upper part of the riser string for releasably connecting the fluid line to the fluid passage to conduct fluid therebetween, said coupling means having a hollow interior of sufficient inside dimensions to permit insertion and removal of the strings without disconnecting the fluid line from the coupling means.
 13. The invention as in claim 12 wherein the coupling means includes: a hollow tubular housing with an open upper end and an open lower end, said housing including an annular flange adjacent the upper end thereof for being mounted to the table structure to locate the upper end of the housing directly below and coaxial with the table structure, a tubular protrusion extending radially outwardly from the housing for connection to the fluid line to receive fluid from the housing, and an inwardly extending upwardly facing landing shoulder formed in the lower end of the housing for receiving a hanger means on the upper part of the riser string.
 14. The invention as in claim 12 wherein the coupling means additionally includes: a tubular insert sized for insertion into the upper open end of the housing to close the upper open end around the operating string run through the housing, said insert having radial passages and a circumferential groove therearound in communication with the radial passages to collect the fluid from the space between the operating string and the riser string and to deliver said fluid to said fluid line.
 15. The invention as in claim 12 wherein the coupling means includes: a hollow elongated housing with open upper and lower ends; means for mounting the housing to the table structure; means for connecting the vessel associated fluid line to the housing; hanger means for removably hanging the upper part of the riser string from within the housing; and means for conducting fluid from the fluid passage to said connecting means.
 16. The invention as in claim 15 wherein the means for conducting the fluid from the passage includes: guide means provided in the housing and having a central bore in communication with the interior of the riser string landed in the housing, said guide means forming a circumferential fluid collecting cavity within said housing and having a plurality of radial passages connecting its central bore therewith, and housing closing means provided in the housing about the operating string and over the guide means for closing the upper open end of the housing above the guide means to prevent the fluid from escaping therethrough.
 17. The invention as in claim 16 wherein the housing closing means includes a tubular insert sized for insertion into the housing, said upper portion of the tubular insert being sized to mate with the hollow of the housing and shaped for receiving a packer insert therein, and includes a packer insert located in said upper portion for engaging the operating string run through the housing.
 18. A method of completing the landing of a riser string between a floating vessel, having a rotary drilling table with a table bore therethrough, and a subsea well comprising the steps of: running a string of tubing through said rotary table bore to said well, and landing a hanger associated with said tubing on a support member associateD with said vessel by running said hanger through said table bore into landed engagement with said member, wherein said member is supported from and beneath said vessel in the sea above said well and said step of running said hanger through said table bore includes the substep of running said hanger into the sea beneath said vessel and into said landed engagement in the sea above and spaced from said subsea well.
 19. A method of completing the landing of a riser string between a floating vessel, having a rotary drilling table with a table bore therethrough, and a subsea well comprising the steps of: running a string of tubing through said rotary table bore to said well, and landing a hanger associated with said tubing on a support member associated with said vessel by running said hanger through said table bore into landed engagement with said member, wherein said member is supported beneath said table and said step of landing said hanger includes the substep of landing said hanger directly below and adjacent to the underside of said rotary table.
 20. A method of completing the landing of a riser string between a floating vessel, having a rotary drilling table with a table bore therethrough, and a subsea well comprising the steps of: running a string of tubing through said rotary table bore to said well, landing a hanger associated with said tubing on a support member associated with said vessel by running said hanger through said table bore into landed engagement with said member, and automatically connecting the interior of said string to a vessel associated line by the landing of said string and associated hanger upon said support member.
 21. A method of completing the assembly of a subsea well assembly comprising the steps of: mounting a tubular open ended housing to the rotating table structure of a floating vessel; running a riser string through the table and housing; and landing an upper end of said string in said housing.
 22. The method of claim 21 including the steps of: coupling a fluid line to the housing; and automatically connecting the interior of the riser string to the housing and the line upon landing the riser string by its hanger means in the housing.
 23. The method as in claim 22 additionally comprising the steps of: inserting a preassembled insert assembly into the housing over the upper part of the riser string; and running an operating string through the insert assembly, through the housing, and into the riser string while the insert assembly closes the upper end of the space between the operating and riser strings.
 24. The method as in claim 23 additionally comprising the steps of: removing the operating string through the housing without disconnecting the fluid lines; and reinserting the operating string through the housing without disconnecting the fluid lines.
 25. A coupling means for coupling a riser string of tubing to a floating vessel over a subsea well to which said string is run, said vessel having a roatry table mounted upon a support on said vessel and having a table bore therethrough and positioned over a path to said well, said coupling means comprising: a riser string supporting means having a central bore to allow passage of said string of tubing therethrough and means for supporting a riser string associated tubing hanger therein, and means for mounting and positioning said supporting means beneath said rotary table with said central bore aligned to said table bore to allow running of said riser string of tubing through said table bore and central bore in said path to said well and said tubing hanger through said table to land on said supporting means. 